Corn Development
The vegetative and reproductive growth stages in corn are described in Table 1–12, Vegetative growth stages in corn and Table 1–13, Reproductive growth stages in corn.
Corn Leaf Stages
Counting the leaves on a corn plant sounds like an easy task, but there are a few complications that can cause mistakes. It is important to know which leaf-counting method is being referred to on pesticide labels or in other production information.
Table 1–14, Comparative growth stages shows comparative growth stages using different methods of counting leaves.
There are several methods used to count corn leaves:
• The leaf-tip method counts all leaves, including any leaf tip that has emerged from the whorl at the
top of the plant.
• The leaf-over method only counts those leaves that are fully emerged and are arched over with the
next leaf visible in the whorl but standing straight up.
• The leaf-collar method, used extensively in the U.S., refers to the leaf collar being visible. The leaf
collar is the light green-to-whitish band that separates the leaf blade from the leaf sheath, which
wraps around the stem. The stages for corn are referred to as V1, V2, V3, etc., where the V3 stage is
a plant with three collars visible.
This is an excerpt of the planting section from the corn chapter of Ontario Ministry of Agriculture, Food and Rural Affair’s “Agronomy Guide for Field Crops – Publication 811”. The whole corn chapter can be viewed as PDF here. All chapters are online, and can be viewed by searching the internet for “Agronomy Guide for Field Crops – Publication 811”. Special thanks to Andrew Priest, OMAFRA summer student, for producing these Field Crop News excerpts.